Balloon gas mixtures



Dec. 17, 1963 w. s. WYMAN EIAL BALLOCN GAS MIXTURES 2 Sheets-Sheet 2 Filed Feb. 25. 1960 A NNW Eu m 000- 001 OON OOO OOQ 00 V CON m -2 325m 3 52:1: & :5

c: "i E 0 E 5 wa t 22% 25 INVENTORS WHITFORD S. WYMAN WILLIAM A. DUNCAN A T TORNEY I United States Patent 3,ll4,7l7 BALLGGN GAS MKXTURES Whitford S. Wyman and William A. Duncan, Toronto, (Pntario, Canada, aseignors to Union Qarbide Canada Limited, a corporation of Toronto, Qatar-i0, Canada Filed Feb. 23, 1960, Ser. No. 10,324 2 (Ilaims. (til. 252--374) This invention relates to balloon gas mixtures. More particularly, it relates to safe and harmless balloon gas mixtures containing little or no helium.

Heretofore, it has been common to fill balloons of the toy and commercial type with helium in order to have a safe gas of suflicient lifting power. These has been some use of hydrogen and so-called illuminating gases (mixtures of hydrogen with methane and similar inflammable gases) in balloons but these gases are so inflammable and explosive as to be highly dangerous and hence completely unsafe for balloon inflation. The current scarcity of helium, occasioned by its vital role in military and scientific applications, led us to search for a suitable substitute gas for such applications as the inflation of toy balloons.

It was believed that the presence of suflicient hydrogen in a gas mixture to impart the lift necessary to float a balloon in air would necessarily result in an explosive or inflammable gas. We have not discovered that such is not the case, however. We have found that mixtures of nitrogen and hydrogen can contain up to 17.5 parts by volume of hydrogen per 100 parts by volume of hydrogen and nitrogen combined without being inflammable and up to 25 parts by volume of hydrogen without being ex plosive. A balloon inflated with this mixture, when ignited by a flame, does not burst violently, as would an explosive gas mixture.

We have made numerous determinations of the gases required to lift different balloons. We found that the proportion of hydrogen required to float balloons depends on the relation of weight of the balloon membrane, the positive lift required and the volume to which it can be inflated. The proportion of hydrogen required depends on the ratio V/L where V is the volume of the inflated balloon and L is the total lift needed, that is, the balloon membrane weight plus the positive lift required. By calculation using the standard densities of air, nitrogen, and hydrogen it is possible to obtain a figure for V/L for any hydrogen/ nitrogen mixtures. From our experiments and calculations we prepared two graphs which are shown in the drawing.

in the drawing:

FIGURE 1 is a graph showing the relationship between the percentage of hydrogen in a hydrogen/nitrogen mixture and the V/L ratio.

FIGURE 2 is a graph showing the relationship between balloon diameter and V/L ratio, assuming a constant surface area per unit weighed of balloon material of 0.707 square feet per gram.

We have found that a mixture of 25 parts by volume hydrogen to 75 parts by volume nitrogen will lift almost any balloon. Such a mixture, while not explosive, is combustible and hence is undesirable for many applications, such as pleasure balloons. A mixture of 17.5 parts by volume hydrogen to 82.5 parts by volume nitrogen is neither explosive nor combustible and hence is entirely safe for all applications. This mixture will not lift very small toy balloons or those of very heavy wall thickness. It will, however, satisfactorily lift thin wall balloons of moderate size, above about 18 inches in diameter for essentially spherical balloons.

3,ll4,717 Patented Dec. 17, 1963 The gas mixture of our invention, therefor contains up to about 25 parts by volume of hydrogen per 100 parts by volume of combined hydrogen and nitrogen. Per 100 parts by volume of combined hydrogen and nitrogen,

from 10 to 25 parts by volume of hydrogen will give a mixture useful in balloons While from 15 to 20 parts by volume of hydrogen will give a safer mixture. It is to be understood that the presence of small quantities of impurities, gaseous or otherwise, and particularly those gaseous impurities commonly found in commercial hydrogen, nitrogen or helium, will in no way remove gas mixtures from the scope of the invention or interfere with the use of the gas mixture to inflate balloons. And while our invention is primarily directed to providing a gas mixture for inflating balloons, our invention is of course useful in any application where a non-combusible or non explosive lighter-than-air gas is desired. It is also within the scope of our invention to substitute another inert gas for part of the nitrogen and to substitute a lighter-than-air gas such as illuminating gas for hydrogen.

In those situations where it is desirable to use less than 25 parts by volume of hydrogen per 100 parts by volume of total gas, thus decreasing the combustibility of the mixture, the lifting power of this quantity of hydrogen in a hydrogen-nitrogen mixture may not be sufficient for the size or weight of the balloon to be lifted. It is within the scope of our invention to add up to 30 parts by volume of helium to a hydrogen-nitrogen mixture in order to achieve greater lift. Per 100 parts by volume of nitrogen, hydrogen and helium, as little as 1 part by volume of helium will improve the lift while from 10 to 15 parts is preferred for maximum benefit. In this embodiment of our invention less than one-sixth the ordinary inventive volume of helium is required in a balloon, thus making possible great savings in the use of this strategic gas.

Such gas mixtures according to our invention may thus comprise, per 100 parts by volume of combined hydrogen, nitrogen and helium, from 10 to 20 parts by volume of hydrogen, from 60 to parts by volume of nitrogen and from 1 to 30 parts by volume of helium. A preferred mixture comprises about 17.5 parts by volume of hydrogen, from about 67.5 to about 72.5 parts by volume of nitrogen and from about 10 to about 15 parts by volume of helium.

What is claimed is:

l. A gas mixture consisting essentially of per 10 0 parts by volume of combined hydrogen, nitrogen and helium, from 10 to 20 parts by volume of hydrogen, from 60 to 90 parts by volume of nitrogen and from 1 to 30 parts by volume of helium.

2. A gas mixture consisting essentially of about 17.5 parts by volume of hydrogen, from about 67.5 to about 72.5 parts by volume of nitrogen and from about 10 to about 15 parts by volume of helium.

References Cited in the file of this patent UNITED STATES PATENTS 1,703,408 Smith Feb. 26, 1929 2,492,800 Isom Dec. 27, 1949 2,602,871 Noland et a1. July 8, 1952 OTHER REFERENCES Bennett et al.: Compressibilities of Mixtures of Hydrogen and Nitrogen above 1000 Atmospheres)? Ind. and Eng. Chem, vol. 44, No. 1, pages 181 and 182 (January 1952). 

1. A GAS MIXTURE CONSISTING ESSENTIALLY OF PER 100 PARTS BY VOLUME OF COMBINED HYDROGEN, NITROGEN AND HELIUM, FROM 10 TO 20 PARTS BY VOLUME OF HYDROGEN, FROM 60 TO 90 PARTS BY VOLUME OF NITROGEN AND FROM 1 TO 30 PARTS BY VOLUME OF HELIUM. 